An inquest has heard how the body of a man was undiscovered for two months despite his father reporting him missing.
Kenneth Palmer, 38, was reported missing to Northamptonshire Police by his father Roy on 11 December 2007.
He was referred to his local police in Lincolnshire where the report was put in a file and not opened until the body was found, the inquest heard.
Mr Palmer Snr blamed police "for a lack of competence and caring".
The inquest heard Mr Palmer Snr, 71, was referred to the Lincolnshire force and saw an officer in his home town of Mablethorpe and filed a report.
It was then meant to be faxed to Northamptonshire Police, but the junior desk officer placed it in a file.
On 21 February 2008 Natasha Richards, his son's neighbour in Brooke Greene, Wellingborough, contacted police.
She said he had looked like a "concentration camp" victim the last time she saw him alive before Christmas 2007, the inquest was told.
When officers broke into his house, they found his body on the bedroom floor.
Part of his body had mummified and his internal organs were badly decomposed, meaning it was impossible to tell how he died although it is believed to be from a combination of malnutrition and alcohol abuse. He had been dead for several weeks, the inquest heard.
Mr Palmer Snr said: "Why did the police not do their job properly and why isn't anybody accountable?
"The police have apologised and we are happy about that but it doesn't mean closure for us.
"We do not believe that police caused Kenneth's death, but we do blame them for a lack of competence and caring.
"There was a window of opportunity of 11 days when, if the system had worked, our son may have been alive. I repeat, may have been found alive."
The inquest heard Mr Palmer's life spiralled out of control after his girlfriend left with their four-year-old daughter after having an affair with one of his colleagues.
Mr Palmer Snr was also critical of the way he was told of his son's death by police.
He was left a voicemail by a Northamptonshire Pc to contact her after his son was discovered.
Despite repeatedly ringing the officer back it was another 22 hours before he was told his son had been found dead, the inquest heard.
The deputy chief constable of Lincolnshire Police Neil Rhodes and the deputy chief constable in Northamptonshire Davina Logan have since visited Mr Palmer Snr and his wife to apologise in person.
Superintendent Mark Lacey, from Northamptonshire Police, said the force had since made changes to its operations room.
He told the inquest: "There were clearly failings on behalf of the control room. They should have accepted the initial call from Mr Palmer and dealt with it at that stage."
Lincolnshire Police said the officer who failed to fax through Mr Palmer Snr's missing person's report had since left the force.
The Independent Police Complaints Commission said a police constable from both Northamptonshire and Lincolnshire police had received "words of advice" following its investigation.
IPCC Commissioner Amerdeep Somal said Mr Palmer's parents were "let down" by both forces.
Anne Pember, coroner for Northamptonshire, recorded an open verdict.